The present invention relates to a hand held flashlight that can generate a spot beam for illuminating distant objects and a flood beam for illuminating near objects as well as to an economically designed flashlight that is capable of effectively exploiting both illumination beams.
A flashlight typically needs to illuminate either distant objects or things that are relatively close. A flashlight that is adapted for illuminating distant objects preferably has a narrowly focused spot beam. A flashlight designed for viewing near objects should have a flood beam to illuminate everything nearby. A spot beam is poorly suited for illuminating a nearby object because the intensity of the illumination is typically too great and the field of illumination is too narrow. Likewise, a flood beam is not suited for illuminating distant objects since the light is too diffuse at the object to illuminate it.
Known hand held flashlights typically generate either a spot beam for illuminating distant objects or a flood beam for illuminating everything nearby. One solution has been to provide a variable focus to the spot beam such that the spot beam can be defocused. A defocused spot beam, however, is not a good flood beam because the distribution of light is highly uneven. The conventional hand held flashlight simply does not provide for generating both spot and uniform flood beams. Attachments have been provided for diffusing the light from the spot beam to form a flood beam. Such attachments, however, are bulky and not practical since they require time to attach and are apt to be lost when separated from the flashlight.
Another solution has been to create a lantern comprising a spot beam and a fluorescent light source, as well as flashing amber light for highway distress. The lantern uses 6 D size batteries and includes a shoulder strap and an adapter for plugging into the cigarette lighter of an automobile. While it does generate both spot and flood beams, the lantern is too large to offer the versatility and ease of use of a conventional hand held flashlight.
The art has yet to produce a hand held flashlight that can generate both a spot beam and a uniform flood beam at the touch of a switch.